It is known to produce gallium-arsenide (GaAs) based N-P-N heterojunction bipolar transistors (HBTs) using traditional semiconductor fabrication techniques. Examples of such transistors are shown and described in the following documents    Streit et al., Monolithic HEMT-HBT Integration by Selective MBE, IEEE Transactions on Electron Devices, Vol. 42, No. 4, April 1995 (see, for example, FIG. 3);    Streit et al., Monolithic HEMT-HBT Integration for Novel Microwave Circuit Applications, GaAs IC Symposium, IEEE, 1994 (see, for example, FIG. 3);    Ho et al., A GaAs BiFET LSI Technology, GaAs IC Symposium, IEEE, 1994 (see, for example, FIG. 1);    Chang, M. F., A Manufacturable GaAs BiFET Technology for High Speed Signal Processing, IEEE, 1995 (see, for example, FIG. 1);    Chang, M. F., Heterojunction BiFET Technology for High Speed Electronic Systems, IEEE, 1997 (see, for example, FIG. 1);    Gupta et al., InGaP-PIus™—A major advance in GaAs HBT Technology, IEEE, 2006 (see, for example, FIG. 1);    Peatman et al., InGaP-PIus™: Advanced GaAs BiFET Technology and Applications, CA MANTECH Conference, May 14-17, 2007, Austin, Tex. (see, for example, FIG. 1);    Lin et al., The Monolithic Integration of InGaAs pHEMT and InGaP HBT Technology for Single-Chip WiMAX RF Front-End Module, IEEE, 2011 (see, for example, FIG. 1); and    Alexandre et al., Quasi-planar GaAs heterojunction bipolar transistor device entirely grown by chemical beam epitaxy, Elsevier Science B.V., North-Holland, Journal of Crystal Growth 136 (1994) 235-240 (see, for example, FIG. 1).    U.S. Pat. No. 4,672,414 and U.S. Patent Application Publication No. US 2002/0064906 also may be relevant.